Windows activation invalid after 8GB upgrade

[Fastblader]

I just upgraded my 2 month old T510 laptop (4314) with 8GB of memory.  It was pre-loaded with Windows 7 Pro x64 and 2GB RAM.  Today I noticed in my System panel that there is "1 day left for automatic windows activation.  Activate now."  I clicked the Activate now and I get a new window that states: "The Windows 7 Professional product key you entered is not valid."  My options are to 1. Buy a new product key 2. Enter a new product key.  3. Contact Lenovo.

I contacted Lenovo and was told that no product key is required for a pre-installed OS.  I might expect a Windows activation for a major hardware change, but not for a memory upgrade.

[lead_org Microsoft MVP Contributor · Accepted solution]

you can use the product key in your battery's laptop compartment to reactiviate the OS.

But i have never personally heard of upgrading ram could cause a need for OS reactivation.

[napalm]

Did you do any other hardware change at same time?

I've just upgraded a T510 from 4GB to 8GB and didn;t have to reactivate.

Nap.

[Fastblader]

Two days later, the message changed to 26 days to automatic activation.  I did not mention that the unit was sent to the depot for repair and I just got it back.  That would have affected the activation status if the motherboard was replaced.  I took your suggestion and re-entered the key under the battery and the activation succeeded.  Thanks for your help.

[lead_org Microsoft MVP Contributor]

a change in the motherboard would require the OS to be reactivated.

[Fastblader]

Of course, because a new motherboard has a different Mac ID.  I should have made that connection.